In copying machines of image type transfer type, there has been proposed to provide a paper separating belt slidably contacted with one side of the surface of a photosensitive drum for assuring separation of a copying paper from the drum. Provision of paper separation device such as paper separation belt results in a loss of image 1a on a side edge portion of a copying paper 1 as shown in FIG. 1 with a width a corresponding to the width of the separation belt. In order to prevent the loss of image, as shown, for example, in Japanese Patent Application laid open under No. 28068/1980, there may be proposed to shift an image 2 in a direction away from the edge near the paper separating belt. However, shifting of the image introduces another loss of image 2a in the edge portion far from the paper separation device, therefore the above proposed approach is not a practical way to solve the above problem.
Besides the above problem, as shown, for example, in U.S. Pat. No. 4,187,024 in the copying machines of the above type, there is employed an arrangement for shifting a timing of paper feeding toward an image transfer portion relative to the timing during which an image formed on the photosensitive drum reaches the image transfer portion so as to provide a binding margin in either the leading edge portion or trailing edge portion of each copied paper. An image loss 1b also happens in either the leading edge portion or trailing edge portion as shown in FIG. 2 in the above arrangement for providing the binding margin.
In order to eliminate the image loss 1a or 1b, it is necessary to adjust copying magnification and particularly in a case where the width of the binding margin is adjustable, it is desired to make the copying magnification adjustable both manually and continuously as shown in Japanese Patent Application laid open under No. 208758/1983 U.S. Pat. No. 4,543,643. However, it may be troublesome to adjust the magnification manually corresponding to the binding margin which is set by the operator as desired so as to form the image on the copying machine as wide as possible over an available area of the copying paper.
On the other hand, as shown, for examples, in U.S. Pat. No. 3,445,161 of Japanese Patent Application laid open under No. 46267/1981, there is proposed an anamorphic magnification copy which is able to vary the magnification in a longitudinal direction and the magnification in a lateral direction. The anamorphic magnification is used for either varying the longitudinal vs lateral ratio of a figure in view of design or eliminating the image loss. Therefore, the anamorphic magnification is effective to make a copy as wide as possible over the available area of the copying paper without image loss.
However, even when anamorphic magnification is used, with the manual setting of the magnification, there still remains the problem of troublesome operation in setting the correct magnification.